Feedback-free internal impinging nozzle, which can generate fan-shape oscillating spray with constant pendulum angle, is well-suitable for flow control, as it has a wide range of operation frequency and does not require additional energy for moving parts. In this study, the spray characteristics of an internal impinging nozzle were investigated in an open atomization test bench by utilizing high-speed Schlieren technology and Malvern particle size analyzer. To better understand the jet oscillation mechanism and to evaluate its impact on the spray sweeping behaviors, a 3D CFD simulation was carried out, which takes the nozzle internal flow dynamics and the external spray morphology into account. The results indicate that the sweeping behavior of the emitted jet is caused by the impingement between two opposite internal jets inside the nozzle. A bi-model spray spatial flow distribution of the nozzle is observed with varying oscillating frequencies and constant spray pendulum angle at different injection pressures. The oscillation process can be divided into two stages depending on jet breakup processes, and the spray waveforms are influenced by the ratio of the durations of these two stages.

无反馈内部冲击喷嘴可产生具有恒定摆角的扇形振荡喷雾，非常适用于流量控制，因为它具有广泛的工作频率范围，并且不需要用于移动部件的额外能量。在这项研究中，利用高速Schlieren技术和Malvern粒度分析仪，在开放式雾化试验台上研究了内部撞击喷嘴的喷雾特性。为了更好地了解射流振荡机理并评估其对喷雾吹扫行为的影响，进行了3​​D CFD仿真，其中考虑了喷嘴内部流动动力学和外部喷雾形态。结果表明，所发射射流的清扫行为是由喷嘴内两个相对的内部射流之间的碰撞引起的。在不同的注射压力下，以不同的振荡频率和恒定的喷雾摆角观察到喷嘴的双模型喷雾空间流量分布。取决于喷射破裂过程，振荡过程可分为两个阶段，并且喷雾波形受这两个阶段的持续时间之比的影响。